Method of making articles of pressed metal



July 29, 1924.

H. G. CARLSON METHOD OF MAKING ARTICLES 0F PRESSED METAL 2 Sheets-$heet1 Filed Dec.

g/drllllllf I H. G. CARL 7 METHOD OF MAKING ARTICLES OF PRESSED METALFiled Dec. 15, 1922 2 Sheets-Sheet 2 (IHEEEQQELE.

Patente July 29, 1924..

HJ'ALMAE, G. CARLSON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR 'I'OROCKWOOD SPRINKLER COMPANY OF MASSACHUSETTS, F WORCESTER, MASSACHUSETTS,A

CORPORATION OF MASSACHUSETTS.

METHOD OF MAKING- .ARTICLES O'F PRESSED METAL.

Application filed December 15, 1922. Serial No. 607,195.

To all whom it may concern:

Be it known that I, HJALMAR G. GARL- soN, a citizen of the UnitedStates, residing at W orcester, in the county of Worcester and State ofMassachusetts, have invented a new and useful Methodof Making Articlesof Pressed Metal, of which the following is a specification.

This invention relates to a method of making of pressed metal hollowarticles which have different portions of varying diameters andthickness ofvstock, such as bolstercases for spinning spindles.

The principal object of this invention is to provide for making sucharticles of pressed metal instead of machining castings or bar stock asheretofore, so that -when they are made in large numbers the expense ofmanufacture will be much re- 2 duced and the articles themselves will belighter in weight and, in the particular use mentioned, bolster cases,oil tight. 7

Reference is to be had to the accompanying drawings, in which- Figs. 1to 9 inclusive are side views, partly or wholly in section, showingsuccessive steps in the manufacture of a spinning spindle bolster casein accordance with this invention;

Fig. 10 is a sectional View on the line 10 10 of Fig. 9;'

Fig. 11 is ja view of the article shown in Fig. 9- with a piece cast onit to complete the bolster case;

35 Figs. 12 and 13 are similar views of modifications; and 1 Figs. 14and 15 are central sectional views of sets of dies for performing someofthe operations.

As stated, the completed bolster case has the appearance indicated inFig. 11 andthe completed part of it that is of pressed metal is shownfully in Figs. 9 and 10.

The process may have more or less steps 45 than indicated in thesedrawings, but with certain kinds and thicknesses 'of metal thisnumberof, steps is suitable. In the first place a round flat blank of sheetsteel (Fig. 1) is pressed by an ordinary die-pressing operation to forma cup as indicated in Fig. 2. By one or more additional operations ofthe same character an elongated cup of smaller diameter is produced as.

than the center.

shown in Fig. 3. -The only difference between the two cups shown inFigs. 2 and 3 'is in the dimensions- No matter how far the reduction isto be made or how many steps are required, a cup is thus provided which,in the three succeeding operations results in cups like Figs. 4, 5 and6, is furtherv elongated and reduced in external diameter and also hasits walls near the open end reduced in thickness, by being forced insuccessive operations through dies by suitable punches, the lowercontacting part of each punch being slightly smaller in diameter thanits upper portion. It will be noticed that the thickness of metal of thecldsed end B has not been changed but fielzmziins the same as that ofthe .original The next step involves the provision of a central enlargedcylindrical part C (Fig;

7). This is done by means of the dies shown in Fig. '14. They involve abase or table 10 having a depression for receiving a plate 11v carryinga cylinder 12 which supports a female die 13. This carries an externaldie 14 held down by a plate 15 adjusted and held by bolts 16. Above thisa female shaping die 17, held in a die plate '18 by a threaded block 19,is pressed down by thepress head above (not shown).

Below in a guide'20 are a set of ejecting plungers 21 'adaptedtobeforced up through the plate 11 to raisea hollow disc 22 in the cylinder-12. On the disc 22 rests an ejector 23 adapted to contact with thebottom A of the article and eject it when the die 17 is raised. Thecentral mandrel 25 is fixed in the center of the bottom plate 11 andcannotmove. This mandrelis the same size throughout and its upper endprojects above the die 14 to serve to center the cup when inserted bythe operator and to hold it when the dies separate so that the operatorcan remove it. Its main function is to regulatethe inside diameter atthe two ends of the cup. It does not come into con- .tact'with theinterior of the enlarged center 0 which it is the purpose of these diesto form by the reduction ,of the ends more tralportionis still the sameas that of the original flat blank and is not changed at all throughoutthe process.

The thickness of the cen- I P the closed end, which is shaped by adie31,

formed in changing this shape to that shown In this operation the blankshown in Fig. 6 is put in the dies over the mandrel 25 with theopen endA resting on the conical depression in the top of the die 14:. Now thedie 18, attached to the press head or plunger, descends from above andmoves.

down to the position shown in Fig. 1 L This reduces the open end A byforcing it through the die 13 and gives it the reduced inside diameterof the exterior of the mandrel 25. Its walls are thickened slightly inthe process.

This die 13 also forms a conical shoulder at D and the die 17 forms asimilar but opposite shoulder at E and also reduces the closed end B.The diameter and thickness of the cylindrical walls of the closed endare both reduced. The central portion G is not modified except at itsends D and E.

By a similar operation this cup is transformed into that shown in Fig.8. The conical sloping shoulderE is shortened to form a more abruptshoulder. The cylindrical closed end is lengthened and reduced indiameter. but not changed in thickness. The open cylindrical end ismodified a little by reducing its length and its diameter. The thicknessof its walls is increased slightly.

All this time the thickness of the metal throughout the part C has notbeen interfered with. In other words, it has been keptilliblsliipntially at the original thickness of the The final metalpressing operation is perin Fig. 9 in which the parts A, Band C areretained in the same shape and relative arrangement as they have been inFig. 8. Now the shoulder E is pressed down by an upsetting die 30 (Fig.15) from-above to form an integral projecting ring or shoulder Dsurrounding the article at the end of the central cylindrical portion C.At the'same'time it is' preferably provided with a plurality of lugs Fintegral ofcourse and standing up from the plane of the shoulder. Theopen end of the cylindrical portion is also reduced by this die 30 toits. final shape; and is of substantially the same internal diameter asand the metal being of nearly the same thickness. The object in leavingthe metal of the central portion C (held in a central die 32)considerably thicker than that of the parts A and B and the samethickness as the original blank, is to provide sufiicient metal for'screw threading. The article is simultaneously pressed down against theejecting plunger 35 which flattens the closed end. The article is shapedin this die the other side up from that'shown in Fig. 14.

In a further operation an inward longitudinal projection 39 may beformed. Such a projection is a substitute for the key that serting a keyin the spindle bolster is av0ided as well as the formation of a grooveon the interior of the bolster casing.

For the purpose of finishing the article, the cup shown in Fig. 9, isplaced in a mold and a casting 40 of malleable cast iron or any otherdesired metal is cast around it. The lugs F are for the purpose offixing it so that it cannot turn on the spindle and the shoulder D isfor holding it against motion longitudinally. This casting is of thesame shape as has been employed heretofore, for conducting oil to thebearing and supportin the hold down. It can be cast in its fina shape asshown in Fig. 11 or can be'cast separately, applied to the casing andthen secured in position by swedging down a cylindrical projection H asshown in Fig. 12. Fig. 13 shows another modification in which the part Cis screw threaded and the casting screwed on.

The foregoing series of operations produces in the forms illustrated, ahollow pressed metal article useful for bolster cases and otherpurposes.

By this method of construction the cost of production in largequantities can be very greatly reduced. Not only this, but the number ofdefective articles is almost eliminated. It is a diflicult thing to boreinto a piece of cast metal the length of this article and secure acentral hole leaving the metal walls of uniform thickness, and it isalso difiicult to stop the boring operation in exactly the right place.Furthermore, the porosity of castings has been found in practice to makethe oil-tightness of cast articles of this type uncertain; for, althoughsuch cast articles may test up all right in response to the ordinarytests, oil will eventually leak through many of the finished articles.My bolster casings, besides being oil tight, are lighter, stronger andcheaper than those made heretofore. The oil-retaining enlargement inpart C has had to be bored out by a special devicehitherto, while by myprocess the enlargement C is cheaply made without employing any extraoperation. These pressed metal articles can be produced accurately inlarge quantities in a small plant with inexpensive tool equipment.

Although I have shown and described the to the use of the method forproducing any one article, but what I do claim is 1. The method ofmaking a long hollow article of pressed metal having'a central portionwith reduced ends, which consists in drawing out a blank of sheet metalto a general cylindrical cup-shape having a closed end and an open end,reducing the diameter and the thickness of metal of the open end by aseries of steps, reducin the diameter and thickness of the extreme cosed end thereof, leaving an intermediate portion. between the open andclosed ends of the cup, and then further drawing out the extreme endswithout materially modifying the thickness of the intermediate portion.

2. The method of making a long hollow article of pressed metal whichconsists in drawing out a flat blank of sheet metal to a generalcylindrical shape havin a convex closed end and an open end, re ucingand elongating the cup and further reducing the thickness of metal ofthe extreme 0 en end, reducing the diameter and the thic ness of metalof the open and closed ends by a series of steps, leaving anintermediate cylindrical portion between the open and closed ends,providing a conical shoulder between the intermediate portion and eachend, then further drawing out the ends without modifying theintermediate portion, but at the same time reducing the thickness of themetal at the open end, and maintaining the original thickness of metalin the intermediate portion throughout the process.

3. The method of making a long hollowarticle of pressed metal whichconsists in drawing out a flat blank of sheet metal to a generalcylindrical shape having a closed end and an open end, reducing the openend and elongating it, reducing the extreme closed end, leaving anintermediate 0 lindrical portion between the open and c osed ends,providing a conical shoulder between the intermediate portion and theclosed end,

' further drawing out the extreme closed end,

reducing the diameter and the thickness of metal of tlfe open'end by aseries of steps, and compressing the shoulder to provide an abruptshoulder at that point.

4. The method of makin a long hollow article of pressed metal w ichconsists in drawing out a fiat blank of sheet metal to a generalcylindrical shape having a closed end and an open end, reducing thediameter of the open end and elongating it, reducing the diameter of theextreme closed end, leaving an intermediate ortion between the open andclosed ends, urther reducing and spindle bolster casing of pressed steelwhich consists in drawing out a blank of sheet metal to a generalcylindrical on having a convex end and an open en ,drawing out the openend to reduce and elongate it, further drawing out the extreme closedend, leaving an intermediate cylindrical fpor tion between the open andclosed ends 0 shape the cup, then further drawing out, reducing andelongating the extreme closed end without materially modifying theintermediate portion, drawing out and reducing the diameter and thethickness of metal of the open and closed ends of the cup withoutmaterially modifying the intermediate portion, upsettin the metal at apoint between the interme iate portion and the open end to form anintegral circumferential rib or shoulder between the two sections, andatthe same time forming integral lugs on said shoulder spaced apart toform a finished pressed metal article, and finally casting metal aroundthe shoulder and lugs, whereby said shoulder will prevent the castingfrom moving longitudinally and the lugs will prevent it from movingcircumferentially.

6. The method of making a hollow article of sheet metal whichcomprisesdrawing out a fiat circular blank of sheet metal by a succession ofdrawing operations into a cup shape, drawing down the thickness of itsopen end, elongating and reducing the external diameter of the entirecup, flattening the closed end thereof, leavin a portion near thethinned open end of su stantially the thickness of the original ,blank.

i 7. The method of making a hollow article of sheet metal whichcomprises drawing out a blank of sheet metal by a succes-

